package org.apache.maven.artifact.resolver.filter;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

/**
 * Filter to only retain objects in the given scope or better. This implementation allows the
 * accumulation of multiple scopes and their associated implied scopes, so that the user can filter
 * apply a series of implication rules in a single step. This should be a more efficient
 * implementation of multiple standard {@link ScopeArtifactFilter} instances ORed together.
 * 
 * @author <a href="mailto:brett@apache.org">Brett Porter</a>
 * @author jdcasey
 */
public class CumulativeScopeArtifactFilter extends AbstractScopeArtifactFilter {

  private Set<String> scopes;

  /**
   * Create a new filter with the specified scopes and their implied scopes enabled.
   * 
   * @param scopes The scopes to enable, along with all implied scopes, may be {@code null}.
   */
  public CumulativeScopeArtifactFilter(Collection<String> scopes) {
    this.scopes = new HashSet<String>();

    addScopes(scopes);
  }

  /**
   * Creates a new filter that combines the specified filters.
   * 
   * @param filters The filters to combine, may be {@code null}.
   */
  public CumulativeScopeArtifactFilter(CumulativeScopeArtifactFilter... filters) {
    this.scopes = new HashSet<String>();

    if (filters != null) {
      for (CumulativeScopeArtifactFilter filter : filters) {
        addScopes(filter.getScopes());
      }
    }
  }

  private void addScopes(Collection<String> scopes) {
    if (scopes != null) {
      for (String scope : scopes) {
        addScope(scope);
      }
    }
  }

  private void addScope(String scope) {
    this.scopes.add(scope);

    addScopeInternal(scope);
  }

  public Set<String> getScopes() {
    return scopes;
  }

  @Override
  public int hashCode() {
    int hash = 17;

    hash = hash * 31 + scopes.hashCode();

    return hash;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }

    if (!(obj instanceof CumulativeScopeArtifactFilter)) {
      return false;
    }

    CumulativeScopeArtifactFilter that = (CumulativeScopeArtifactFilter) obj;

    return scopes.equals(that.scopes);
  }

}
